Resource descriptor synthesized from OTLP metrics requests, so the entity
graph reads one table instead of scanning every logical metric table for
attributes the promote filter may have dropped.
Prometheus-style (job, instance) identity. Per the OTel Prometheus
compatibility spec job folds in service.namespace when present; a
resource without service.name gets no job rather than a fabricated one.
Both fields are optional strings, so a named type keeps a swapped
destructuring from type-checking at the call sites.
The tables a metric emits and their per-table metric.type. Histogram fans
out into _bucket (the histogram) plus _sum/_count counters; summary
fans out into the quantile table plus _count/_sum counters (legacy
summary stays a single table).
Whole-metric acceptance, decided once for the encoder and for the resource
descriptor, which must not describe a resource whose data was rejected.
Individual points can still fail exponential_histogram_value.